Cerebroside sulfotransferase is a membrane-bound enzyme which is involved in transferring a sulfate group from 3'phosphoadenosine 5'phosphosulfate to galactosylceramide to form sulfogalactosylceramide (sulfatide). Sulfatide is found in high concentration in the nervous system where its function is unknown. Accumulation of sulfatide in humans produces a rapidly progressive neurological disease. A first step in understanding the function of sulfatide would be knowledge on the synthesis and the regulation of the synthetic enzyme. We have purified the enzyme protein from rat kidney and localized the enzyme by immunohistochemical methods. Currently we are attempting to purify the enzyme from rat brain and produce monoclonal antibodies against the antigen. The antibodies obtained will be utilized to study the synthesis and turnover of the enzyme protein during normal periods and when myelination is perturbed.